Y Combinator's well-known CEO, Garry Tan, revealed to a SXSW crowd that he is experiencing "cyber psychosis" and getting very little sleep due to his intense enthusiasm for working with AI agents. "I sleep like four hours a night right now," he stated during an on-stage conversation on Saturday with fellow venture capitalist Bill Gurley. He humorously remarked about his current AI fixation, "I have cyber psychosis, but I think like a third of the CEOs that I know have it as well." (The comment was presumably in jest, though AI-induced psychosis can be a serious concern.)

He drew a comparison to his past entrepreneurial efforts, saying, "Once you try it, you’ll realize: it’s like I was able to recreate my startup that took $10 million in VC capital and 10 people, and I worked on that for two years, and I took anti-narcoleptics - like I remember, you know, sort of being on like modafinil." He was referring to the wakefulness-promoting drug often associated with startup culture. (Tan previously sold his Y Combinator-backed blogging platform, Posterous, to Twitter in 2012.)

Now, however, his mind is so energized by collaborating with AI agents that it creates a natural state of insomnia. "I don’t need modafinil with this revolution. Like I’m up. I slept at 4 a.m. I woke up at 8 a.m.," he explained. "I wanted to sleep more, but I couldn’t because: let’s see what’s going on with the 10 workers. I’ve got like three different projects going right now."

His excitement led him to freely share his personal Claude Code (CC) configuration on GitHub under an open-source license on March 12, just two days before the interview. This setup, which he named "gstack," included six "opinionated" Claude Code skills he created. These skills are reusable prompts stored in specific files. "I’ve been having such an amazing time with Claude Code, I wanted you to be able to have my *exact* skill setup," he announced in a post on X.

He has since expanded the collection with additional skills. While the gstack GitHub repository currently lists 13 skills, Tan frequently posts about new developments. In one example, he demonstrated his workflow: he first uses a skill where Claude acts as a CEO to evaluate a startup idea, then another where Claude writes the code as an engineer, and a third where Claude reviews its own work for bugs as a code reviewer. Other skills handle design, documentation, and similar tasks.

The response to gstack was immediate and significant. His post went viral on X, trended on Product Hunt, and has garnered nearly 20,000 stars on GitHub with 2,200 "forks," indicating many users have copied the files to adapt for their own use. However, the release also sparked considerable criticism. A subsequent tweet from Tan, in which he quoted a CTO friend calling gstack "god mode" for instantly finding a security flaw, attracted a wave of negative reactions.

The critical responses were pointed. One founder posted on X, "1) Garry should be embarrassed for tweeting this. (2) If it’s true, that CTO should be fired immediately."

Vlogger Mo Bitar produced a segment titled “AI is making CEOs delusional,” arguing the project was essentially "a bunch of prompts" in a text file. He echoed a common critique that developers using Claude Code often create similar setups themselves. A comment on Product Hunt added, "Garry, let’s be clear and honest: if you weren’t the CEO of YC, this wouldn’t be on PH."

This raises the question: is gstack a uniquely useful tool for working with Claude Code, or is it unremarkable? Several AI experts were consulted for their perspective, including Claude itself, which unsurprisingly praised the setup. ChatGPT and Gemini also responded positively.

ChatGPT described gstack as a collection of "reasonably sophisticated prompt workflows, but they’re not ‘magical.’" It noted, "The real insight here is that AI coding works best when you simulate an engineering org structure. Not when you just ask: ‘build this feature.’"

Gemini called the configuration "sophisticated," stating that "gstack is essentially a ‘Pro’ configuration. It is less about making coding easier and more about making it correct."

Claude characterized gstack as "a mature, opinionated system built by someone who actually uses it heavily," adding, "It’s one of the better examples of Claude Code skill design out there." This can be taken as a strong endorsement from an authority on the subject.

In a follow-up post on X this Monday, Tan elaborated on his passion, writing, "I took modafinil just to stay awake longer to be able to turn the momentary crystalline structures I had in my brain into lines of code before sleep or human distraction turned it to grains of sand. I love coding but I love coding with AI even more. I speak it listens and we create. I see the structure and it is built. There is no more powerful an experience to me than that."

Tan did not reply to multiple inquiries for comment.